We studied the rate of predation on artificial and natural nests of Great Reed Warbler Acrocephalus arundinaceus in two contrasting vegetation types, reed Phragmites australis and reed mace Typha angustifolia beds. Reed provided thinner and taller stems to attach a nest to than reed mace, and reed mace provided more cover in late spring, but not in early spring. Nest density, the distance of nests from the water edge, and the timing of breeding differed considerably between vegetation types. However, there were no differences in survival rates of natural nests between both habitats. Artificial nests, on the contrary, were more frequently depredated in reed beds. Based on peck marks left on plasticine eggs, 74% of identified nest predators were large birds in both reed and reed mace beds. There was no correlation between the predicted predation rate of natural nests (derived from a logistic regression model using artificial nests) and the observed predation rate of natural nests, suggesting parental nest defence behaviour or subtle differences between actual nest sites and artificial nest sites might account for the observed discrepancy between natural and artificial predation rates. We suggest that interactions between vegetation structure, nest site choice and parental behaviour may have influenced nest predation rates in the Great Reed Warbler.